Safety ratchet mechanism

Abstract

A hand tool having first and second handle portions and a toothed bar that has first and second terminal ends, a plurality of teeth having free ends, and at least one shield member adjacent the teeth and having at least a portion which extends beyond the free ends of the teeth, wherein the toothed bar is pivotally attached at its first terminal end to a first handle portion and the teeth of the toothed bar engage with a pawl associated with the second handle. The invention is also directed to a safety ratchet mechanism for preventing undesired relative movement of two handle portions of a hand tool, wherein the toothed bar has a first end that is pivotally connected to at least one handle portion and a second end adapted and configured to move relative to the second handle portion when the handle portions undergo relative movement, and wherein the toothed bar has a plurality of teeth that are designed to interact with a pawl. The toothed bar may further have two shield members with the teeth extending therebetween to further shield the operator's hands or gloves from the teeth. The second handle portion may have an opening through which the toothed bar can slide, and a catch may be mounted on the toothed bar to prevent it from sliding out of the opening, and a stop may be associated with the handle to prevent the second end from being disassociated with the handle portion.

What is claimed is:  
     
       1. A surgical hand tool comprising: 
       first and second handle portions, the second handle portion having a pawl associated therewith;  
       a toothed bar having a longitudinal axis, the bar comprising first and second terminal ends, a plurality of teeth configured to engage the pawl, and at least one shield member adjacent the teeth and extending both along the direction of and transverse to the longitudinal axis of the tooth bar, the shield member having an upper edge extending along the direction of the longitudinal axis, the teeth recessed below the upper edge of the shield for protecting the hand of a tool user from cuts;  
       wherein the toothed bar is pivotally attached at its first terminal end to the first handle portion and the teeth of the toothed bar are adapted to engage the pawl associated with the second handle portion.  
     
     
       2. The hand tool according to  claim 1  wherein the first handle portion comprises a biasing spring adapted and configured to pivot the toothed bar into engagement with the pawl. 
     
     
       3. The hand tool according to  claim 2  wherein the biasing spring comprises a leaf spring mounted to the first handle portion. 
     
     
       4. The hand tool according to  claim 1  wherein the second handle portion has an opening and the toothed bar slides through said opening. 
     
     
       5. The hand tool according to  claim 4  wherein the toothed bar comprises a catch to prevent the toothed bar from sliding through the opening. 
     
     
       6. The hand tool according to  claim 1  wherein the second handle portion has a stop to prevent the toothed bar from pivoting away from the pawl. 
     
     
       7. The hand tool according to  claim 1  wherein the toothed bar has two shield members. 
     
     
       8. The hand tool according to  claim 1  wherein the plurality of teeth comprises two rows of teeth and wherein the at least one shield member is located between said two rows of teeth. 
     
     
       9. The hand tool according to  claim 8 , further comprising two additional shield members, wherein the two rows of teeth are located between the two additional shield members. 
     
     
       10. The hand tool according to  claim 8  wherein the two rows of teeth have two exposed lateral edges, said exposed lateral edges being tapered toward the at least one shield member. 
     
     
       11. The hand tool according to  claim 1  wherein the toothed bar is releasably attached at its first terminal end to the first handle portion. 
     
     
       12. The hand tool according to  claim 1  wherein the toothed bar is machined. 
     
     
       13. The hand tool according to  claim 1  wherein the teeth and pawl are arranged as corresponding sawtooth serrations. 
     
     
       14. A ratchet mechanism for preventing undesired relative movement of two handle portions of a surgical hand tool comprising: 
       a toothed bar having a longitudinal axis, the bar comprising a first end adapted and configured to be pivotally connected to at least one handle portion and a second end adapted and configured to move relative to the other handle portion when the handle portions undergo relative movement, the toothed bar having a plurality of teeth designed and configured to interact with a pawl on the hand tool, and at least one shield member adjacent the toothed bar and extending both along the direction of and transverse to the longitudinal axis of the tooth bar, the shield member having an upper edge extending along the direction of the longitudinal axis, the teeth recessed below the upper edge of the shield for protecting the hand of a tool user from cuts.  
     
     
       15. The ratchet mechanism according to  claim 14  wherein the other handle portion has an opening and the toothed bar slides through said opening. 
     
     
       16. The ratchet mechanism according to  claim 15  wherein the toothed bar comprises a catch to prevent the toothed bar from sliding through the opening. 
     
     
       17. The ratchet mechanism according to  claim 16  wherein the first end of the toothed bar is designed and configured to receive a biasing force to pivot the toothed bar into engagement with the pawl. 
     
     
       18. The ratchet mechanism according to  claim 17  wherein the first end of the toothed bar is designed and configured to interact with a free end of a leaf spring mounted to the handle portion of the hand tool. 
     
     
       19. The ratchet mechanism according to  claim 14  wherein the toothed bar has two shield members. 
     
     
       20. The ratchet mechanism according to  claim 14  wherein the plurality of teeth comprises two rows of teeth and wherein the at least one shield member is located between said two rows of teeth. 
     
     
       21. The ratchet mechanism according to  claim 20 , further comprising two additional shield members, wherein the two rows of teeth are located between the two additional shield members. 
     
     
       22. The ratchet mechanism according to  claim 20  wherein the two rows of teeth have two exposed lateral edges, said exposed lateral edges being tapered toward the at least one shield member. 
     
     
       23. The ratchet mechanism according to  claim 14  wherein the first end of the toothed bar is detachable from the at least one handle portion. 
     
     
       24. The ratchet mechanism according to  claim 14  wherein the toothed bar is machined. 
     
     
       25. The ratchet mechanism according to  claim 14  wherein the toothed bar is designed and configured to prevent the handle portions from separating unless the operator disengages the teeth from the pawl. 
     
     
       26. The ratchet mechanism according to  claim 14  wherein the teeth are arranged as sawtooth serrations. 
     
     
       27. A surgical hand held tool comprising: 
       a first extending member;  
       a second extending member having an opening associated therewith and a pawl;  
       a working end movable by relative movement of the extending members;  
       a toothed bar having a longitudinal axis, the bar having a first end pivotally connected to the first extending member and a second end adapted and configured to move through the opening in the second extending member, the toothed bar having teeth adapted and configured to engage with the pawl, and at least one shield member adjacent the teeth and extending both along the direction of and transverse to the longitudinal axis of the tooth bar, the shield member having an upper edge extending along the direction of the longitudinal axis, the teeth recessed below the upper edge of the shield for protecting the hand of a tool user from cuts; and  
       a biasing member to urge the teeth into engagement with the pawl;  
       wherein the toothed bar and second extending members are designed and configured so that the toothed bar does not become disassociated from the second extending member.  
     
     
       28. The hand held tool according to  claim 27 , configured and adapted so that the first and second extending members can be moved relative to each other in both directions by use of one hand of the operator. 
     
     
       29. The hand held tool according to  claim 27  wherein the toothed bar has a longitudinal axis between the first end and the second end and wherein the teeth and pawl are configured to have contact surfaces that are substantially perpendicular to the longitudinal axis of the toothed bar. 
     
     
       30. The hand held tool according to  claim 27  wherein the toothed bar is curved. 
     
     
       31. The hand held tool according to  claim 27  wherein the opening has a stop to prevent the toothed bar from being disassociated with the second extending member. 
     
     
       32. The hand held tool according to  claim 31  wherein the stop prevents the toothed bar from pivoting away from the second extending member. 
     
     
       33. The hand held tool according to  claim 27  wherein the toothed bar has a catch to prevent the toothed bar from sliding through the opening. 
     
     
       34. The hand held tool according to  claim 33  wherein the opening has a U-shape having an open back. 
     
     
       35. The hand held tool according to  claim 27  wherein the biasing member is a leaf spring associated with the first extending member, and further comprising a pivotal connection wherein the leaf spring biases the toothed bar to rotate about the pivotal connection. 
     
     
       36. The hand held tool according to  claim 27  wherein the biasing member engages the toothed bar and the second extending member. 
     
     
       37. A surgical hand tool comprising: 
       a first extending member;  
       a second extending member having an opening associated therewith and a pawl;  
       a working end movable by relative movement of the extending members for performing a surgical procedure;  
       a toothed bar having a longitudinal axis, the bar having a first end pivotally connected to the first extending member and a second end, the toothed bar having teeth adapted and configured to engage with the pawl, and at least one shield member adjacent the teeth and extending both along the direction of and transverse to the longitudinal axis of the tooth bar, the shield member having an upper edge extending along the direction of the longitudinal axis, the teeth recessed below the upper edge of the shield for protecting the hand of a tool user from cuts,  
       wherein at least a portion of the edge extends beyond the free ends of the teeth.